JPH07167958A - Obstacle sensing device - Google Patents

Abstract

PURPOSE:To provide an obstacle sensing device which is less restrictive for the sensible range and is safe even for a person by furnishing a drive voltage control circuit to control the voltage of drive pulses to be impressed on a light emitting element, and controlling the transmitted light powers in different angular directions individually. CONSTITUTION:From a light sending device 1 a plurality of angular directions and pulse beams are generated, and the distance from an object concerned is sensed on the basis of the time difference between beam sending-off and reception of the reflected light. The arrangement includes a steering wheel angle sensor 8 to sense the angle of the steering wheel of car and a car speed sensor 9 to sense the car speed. The charging voltages of capacitors 12a-12n are controlled by controlling the current feed times for transistors 14a-14n with drive voltage control circuits 11a-11n in conformity to the input signal. Thereby the sent-off light powers from laser diodes 16a-16n can be increased or decreased in individual directions of projection angle. This increment or decrement of the power can be achieved simply by reducing the power, widening the light emitting interval, or widening the spreading angle of each beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an obstacle detecting device for a vehicle, and more particularly to an obstacle detecting device using an optical laser.

[0002]

2. Description of the Related Art As this type of distance measuring device, there is, for example, a device disclosed in Japanese Patent Publication No. 2-228579. FIG. 8 is an example of the configuration diagram, 1 is a light transmitting device that drives a plurality of light emitting elements such as a laser diode to emit pulsed light in a plurality of angular directions, and 2 is a clock pulse that is a timing of emitting pulsed light. A light receiving device for converting the reflected pulsed light from the object 7 irradiated with the pulsed light into an electric signal, and 4 for measuring the clock pulse and measuring the clock pulse by the time interval corresponding to the count value. A sample pulse generator that delays the pulse to generate a sample pulse, 5 is a sample hold circuit that samples the output signal of the light receiving device 3 with the sample pulse generated from the sample pulse generator 4, and 6 is the light transmitting device 1 and the sample pulse It is a processing device that controls the generator 4 and takes in the output signal waveform of the sample hold circuit 5 to calculate the distance.

Next, the operation of the conventional device thus constructed will be described. The clock generator 2 generates a clock pulse, and the light transmitting device 1 emits pulsed light in synchronization with the clock pulse. This pulsed light is reflected by the object 7, and the light receiving device 3
Is received as reflected light. The light receiving device 3 photoelectrically converts this pulsed light into an electric signal, and then inputs the output signal to the sample hold circuit 5. On the other hand, the sample pulse generator 4 counts the clock pulses from the clock generator 2 and generates a sample pulse delayed from the clock pulse by a time obtained by multiplying the count value N by Δt corresponding to the distance resolution. The sample hold circuit 5 samples the light receiving signal emitted from the light receiving device 3 by this sample pulse, and holds it until the next sample. The processing device 6 compares the output signal of the sample hold circuit 5 with a threshold value L for reflected pulse light detection, detects a signal equal to or higher than the threshold value L, and counts the clock pulse count value N of the sample pulse generator 4 at that time. Is calculated according to the following equation, and the distance R to the object is calculated. Here, c represents the speed of light.

R = N * Δt * c / 2 (Equation 1)

That is, the round trip distance to the object is obtained by multiplying the time difference between the light transmission and the light reception obtained from the clock pulse count value N by the speed of light, and the half of the distance is the obtained distance. The count value N of the clock pulse returns to 0 when the count value reaches a value corresponding to the maximum detection distance. It is possible to continuously measure the distances to the obstacles in the plural angle directions by sequentially repeating the distance measurement in the plural angle directions with the above operation as one cycle.

In the distance measuring device using the above-mentioned conventional technique, the distance cannot be measured unless the received light power is equal to or more than the above threshold value L, and when an obstacle at a long distance is targeted, a large amount of light is transmitted. Light power is needed. On the other hand, in consideration of safety to human eyes, it is necessary to prevent the light transmission power from being increased more than necessary. For this reason, there has been proposed a method of controlling the light transmission power according to the vehicle speed, the external brightness, etc., as in Japanese Patent Laid-Open No. 49-16463.

[0007]

However, in the method of controlling the light transmission power by the vehicle speed, the output of the laser light is reduced when the vehicle speed becomes low regardless of whether or not there is an obstacle in the front short distance. Therefore, there is a problem in that the optical output of the laser radar is narrowed down even if a person is not actually within the range affected by the laser, which unnecessarily limits the detectable range. Therefore, an object of the present invention is to obtain an obstacle detection device that does not unnecessarily limit the detectable range and is safe for humans.

[0008]

According to a first aspect of the present invention, there is provided an obstacle detecting device for detecting a distance to an obstacle in each of a plurality of angular directions. The power can be controlled individually for each angle direction.

Further, in the obstacle detecting device according to the second aspect of the present invention, the power of the outgoing light is individually controlled for each angular direction so that the reception intensity of the reflected light for each angular direction falls within a predetermined range. To do.

Further, in the obstacle detecting device according to the third aspect of the present invention, the power of the transmitted light is reduced with respect to the angle direction when an obstacle (pedestrian) in a short distance is detected.

Further, in the obstacle detecting device according to the fourth aspect of the present invention, the power of the outgoing light in the angular direction outside the vehicle traveling direction is set to an intensity smaller than the power of the outgoing light in the vehicle traveling direction. To do.

Further, in the obstacle detecting device according to claim 5 of the present invention, when an obstacle at a short distance is detected,
The power of the outgoing light in the angular direction adjacent to the angular direction in which the obstacle is present is limited.

Further, in the obstacle detecting device according to claim 6 of the present invention, the obstacle is constructed so as to estimate the position, size, etc. of the vehicle or the like based on the distances to the obstacle in a plurality of angular directions. In the obstacle detection device, based on parameters such as the distance from the obstacle vehicle and the transmission / reception intensity in the angular direction corresponding to the reflector attached to the obstacle vehicle, etc., it is sufficiently safe for the occupants of the obstacle vehicle. The power of the transmitted light in the angle direction portion of the predetermined range with respect to the obstacle vehicle is controlled so that the light intensity is obtained.

Further, in the obstacle detecting device according to the seventh aspect of the present invention, when the distance to the detected obstacle (pedestrian) is short, or when the reception intensity of the reflected light is higher than necessary, the transmitted light is transmitted. The power density of the transmitted light is reduced by widening the angular width of.

[0015]

According to the obstacle detecting device according to the first, second, third and seventh aspects of the present invention, the reception intensity of the reflected light when the obstacle is at a long distance or in the case of fog, etc. If the power is weak, raise the power of the transmitted light as necessary. Conversely, if the distance from the obstacle (pedestrian) is short or if the received intensity of the reflected light is large, the transmitted light in that angle direction is By reducing the power or widening the irradiation angle per transmitted light, the power density can be reduced to protect the safety of pedestrians.

Further, according to the obstacle detecting device of the fourth aspect of the present invention, since it is not necessary to detect a long distance for an obstacle slightly lateral to the traveling direction of the vehicle, it is possible to detect the obstacle to the side. By limiting the light transmission power, it is possible to secure safety for pedestrians who are passing by the road.

Further, according to the obstacle detecting device of the fifth aspect of the present invention, by limiting the power of the transmitted light in the angular direction adjacent to the angular direction in which the obstacle at a short distance exists, the obstacle is detected. When a person is present in the direction, it is possible to avoid the risk that the face or the like of the person moves in the angular direction and receives the transmitted light of strong power.

Further, according to the obstacle detecting apparatus of the sixth aspect of the present invention, when it is recognized that another vehicle is present at a short distance, the light transmission power in the vehicle compartment direction is reduced. It is possible to secure the safety of passengers in the adjacent vehicle.

[0019]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. The schematic block configuration of the first embodiment is the same as that of FIG. FIG. 1 is a circuit configuration diagram showing the inside of the light transmitting device 1 according to the first embodiment. In the figure, 11a to 11n are drive voltage control circuits for controlling the voltage of a drive pulse applied to a laser diode (light emitting element) described later, and 12
a to 12n are capacitors for storing energy for causing the light emitting elements 16a to 16n to emit light, and 13a to 13n.
Is a resistor that limits a charging current when charging the capacitors 12a to 12n, and 14a to 14n are capacitors 12a to 1
2n is a transistor for controlling the timing and time of charging, 15a to 15n are diodes for blocking a sneak current between the laser diode drive circuits, 16a to 16n are laser diodes provided for each irradiation angle direction, Reference numeral 17 denotes laser diodes 16a to 1
Thyristors for performing timing control of the pulse-like drive current flowing to 6n, and 18a to 18n are lenses for condensing the light emitted by the laser diodes 16a to 16n. In this circuit, the charging voltage of the capacitors 12a to 12n can be controlled by controlling the energization time of the transistors 14a to 14n by the input signal C. As a result, the power of the light emitted from the laser diodes 16a to 16n can be controlled in each irradiation angle direction. You can increase or decrease each time. Such power increase / decrease can be achieved by simply lowering the power, widening the interval of the light emission period, or widening the divergence angle of one beam.

The operation of the apparatus of this embodiment will be described with reference to FIG. In FIG. 2, S1 to S4 denote output signals of the sample and hold circuit 5, that is, signals corresponding to light receiving signals, L is a threshold value for distance detection, and H1 is a threshold value L.
The lower limit of the light receiving target is set to a larger value, and H2 indicates the upper limit of the light receiving target. In the apparatus of the present embodiment, when the light reception signal exceeds the light reception target upper limit value H2, the intensity of the light emitted in the next same direction is lowered, and when the light reception signal does not exceed the light reception target lower limit value H1, the following By increasing the intensity of the outgoing light in the same direction, the power of the outgoing light is controlled so that the peak value of the received light waveform falls within the range of approximately H1 to H2. As a result, it is possible to radiate the emitted light with the minimum required power for each angular direction, and it is possible to improve safety without impairing the obstacle detection function. Further, since the intensity of the received waveform is stable, the variation in the time until the received waveform crosses the threshold value is reduced, and as a result, the variation in the detected value of the distance can be suppressed. Furthermore, when starting the detection of the obstacle, first, the transmitted light of sufficiently low power is first radiated, and the power is sequentially increased in accordance with the received light intensity, so that the danger at the start of the detection can be avoided. Further, by making H1, H2, and L variable according to parameters such as the distance from the obstacle, more detailed control becomes possible. Here, the light transmitting device 1 and the processing device 6 are claimed in claims 1 and 2.
It constitutes the sending light control means.

Example 2. FIG. 3 is a configuration diagram of the device of the second embodiment, and has a configuration in which a steering wheel angle sensor 8 that detects the angle of the steering wheel of the vehicle and a vehicle speed sensor 9 that detects the vehicle speed are added to the device of the first embodiment. . In the figure,
The same reference numerals as those in FIG. 8 indicate the same or corresponding portions.

The operation of the apparatus shown in FIG. 3 will be described with reference to FIG. FIG. 4 (a) shows a case where a vehicle equipped with this device is traveling straight ahead. In the case of a straight-ahead state, the direction in which the vehicle is heading and the road are in the same direction, so the distance information in the angular direction near the center line of the vehicle indicates the road situation in the front. Although it is necessary to detect obstacles to a considerable distance corresponding to each other, only information about extremely short distances is required in the angular directions on both outer sides with respect to the center line of the vehicle. Not only that, but it also poses a danger to pedestrians on the side of the road because it emits light from a short distance. Therefore, as shown in the figure, the detection distance required for the function is set for each angle direction,
Especially, strong light was not emitted toward the pedestrians on the roadside.

Next, FIG. 4 (b) shows a case where a vehicle equipped with this device is traveling on a left curve. When traveling on a curve, the distance information in the angular direction slightly to the left of the own vehicle center line indicates the road condition ahead, and obstacles are detected up to a considerable distance corresponding to the vehicle speed in this angular direction. Although it is necessary, only the information of a very short distance is required in the angle direction on the outer right side with respect to the center line of the own vehicle, and the transmitted light power can be weak in this angle direction. It should be noted that the detection distance for each angle direction that is functionally required varies depending on vehicle driving conditions such as the steering wheel angle and the vehicle speed. In addition, for a moving object recognized as a moving vehicle due to conditions such as relative vehicle speed, by controlling the output light power in the direction of the moving object so that supplementation can be continued, for example, a steering wheel near the entrance of a curve. It is possible to continue measuring the inter-vehicle distance without losing sight of the preceding vehicle even under the condition where the road ahead is curved despite the corner being straight. Example 2
Also in the above, the light sending device 1 and the processing device 6 constitute the sending light control means of claim 4.

Example 3. The configuration of the third embodiment is the same as that of FIG. 3, and only the inside of the processing device 6 has different processing contents. The operation of this embodiment will be described with reference to FIG. This device detects the distances to obstacles in a plurality of angular directions, extracts those having similar distances and relative speeds to the own vehicle from the information, and ties objects whose mutual distances are shorter than a predetermined value, It is recognized as one vehicle by considering these as the reflector attached to the rear side light of the preceding vehicle or the body portion therebetween. The power of the transmitted light in each angle direction is the first embodiment.
The same configuration as above limits the minimum power required to detect obstacles, but the reflected light in the direction of the light source may be extremely weak, as in the case of a painted body, for example. The power of the transmitted light in the direction of the body portion may not be sufficiently narrowed. In such a case, it is difficult to say that the occupant of the preceding vehicle looks back and is sufficiently safe. In consideration of this point, the present device secures the safety of the occupant of the preceding vehicle by reducing the power of the emitted light in the angular direction corresponding to the vehicle width after the vehicle is recognized as a vehicle. Similarly, by reducing the power of the emitted light in the angular direction corresponding to the portion closest to the outer side of the vehicle width, when the driver of the preceding vehicle confirms the rear through the side mirror, or when the fellow passenger sees his face through the window. Ensure safety when you look out behind you. In the third embodiment, the light transmission device 1 and the processing device 6 constitute the transmission light control means of claims 5 and 6.

Example 4. The configuration of the fourth embodiment is the same as that of the first embodiment, and only the contents inside the light transmitting device 1 and the processing device 6 are different. FIG. 6 shows the internal structure of the light transmitting device. The difference from the first embodiment in the figure is that the lens moving device 19 can adjust the distance from the laser diode to the lens 18 to control the spread of the transmitted light. As a result, as shown in FIG. 7, when the distance to the obstacle is short, the spread of the transmitted light is increased to reduce the power density. In this case, the light transmission device 1 and the processing device 6 constitute the transmission light control means of claim 7. At the same time, by increasing the light emission period, the number of transmitted lights is reduced with respect to the angle direction, so that the power is reduced and one person is not irradiated with the emitted light in a plurality of angle directions in duplicate. To ensure safety for people. In this case, the light sending device 1 and the processing device 6 constitute the sending light control means of claims 3 and 6.

As described above, according to the first to fourth embodiments of the present invention, in the device for detecting the distance to the obstacle in each of the plural angular directions, the power or the light emission of the transmitted light in the plural angular directions. The cycle or divergence angle can be controlled individually for each angular direction, and the power of the transmitted light can be controlled individually for each angular direction so that the received intensity of the reflected light for each angular direction falls within a predetermined range. , When detecting an obstacle at a short distance, widen the angular width of the transmitted light or thin out the number of transmitted light in the angular direction to reduce the power density or the number of transmitted light received by a pedestrian, or to advance the vehicle. Reduce the power of the transmitted light outside the direction, or
Provide an obstacle detection device using an optical laser that is safe for pedestrians and vehicle occupants by limiting the power of light emitted in the direction corresponding to the cabin of the obstacle vehicle and its immediate outside. it can.

[0027]

In the obstacle detecting device according to the first aspect of the present invention, in the device for detecting the distance to the obstacle in each of a plurality of angular directions, the power of the transmitted light in a plurality of angular directions is changed. Since it can be controlled individually for each direction, the detectable range is not unnecessarily limited,
Moreover, it is possible to obtain an obstacle detection device that is safe for humans.

Further, in the obstacle detecting device according to the second aspect of the present invention, the power of the outgoing light is individually controlled for each angular direction so that the reception intensity of the reflected light for each angular direction falls within a predetermined range. As a result, there is an effect that the detectable range is not unnecessarily limited, and an obstacle detection device that is safe for humans can be obtained.

In the obstacle detecting device according to the third aspect of the present invention, the power of the transmitted light is reduced with respect to the angle direction when an obstacle (pedestrian) in a short distance is detected. There is an effect that the detectable range is not unnecessarily limited, and an obstacle detecting device that is safe for humans can be obtained.

In the obstacle detecting device according to the fourth aspect of the present invention, the power of the outgoing light in the angular direction outside the vehicle traveling direction is set to an intensity smaller than the power of the outgoing light in the vehicle traveling direction. As a result, there is an effect that the detectable range is not unnecessarily limited, and an obstacle detection device that is safe for humans can be obtained.

Further, in the obstacle detecting device according to claim 5 of the present invention, when an obstacle at a short distance is detected,
Since the power of the outgoing light in the angular direction adjacent to the angular direction in which the obstacle exists is limited, the detectable range is not unnecessarily limited, and the obstacle is safe for humans. It is possible to obtain the object detection device.

Further, in the obstacle detecting device according to the sixth aspect of the present invention, the obstacle is constructed so as to estimate the position, size, etc. of the vehicle or the like based on the distances to the obstacle in a plurality of angular directions. In the obstacle detection device, based on parameters such as the distance from the obstacle vehicle and the transmission / reception intensity in the angular direction corresponding to the reflector attached to the obstacle vehicle, etc., it is sufficiently safe for the occupants of the obstacle vehicle. Since the power of the transmitted light in the angular direction portion of the predetermined range with respect to the obstacle vehicle is controlled so that the light intensity is obtained, the detectable range is not unnecessarily limited, and the human Also has the effect of being able to obtain a safe obstacle detection device.

Further, in the obstacle detecting device according to claim 7 of the present invention, when the distance to the detected obstacle (pedestrian) is short, or when the received intensity of the reflected light is higher than necessary, the transmitted light is transmitted. Since the power density of the transmitted light is reduced by widening the angle width of the object, an obstacle detection device that does not unnecessarily limit the detectable range and is safe for humans is obtained. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing the inside of a light transmitting device.

FIG. 2 is an operation explanatory diagram illustrating an operation of the first embodiment.

FIG. 3 is a block diagram of an apparatus according to a second embodiment.

FIG. 4 is an operation explanatory diagram illustrating an operation of the second embodiment.

FIG. 5 is an operation explanatory diagram illustrating an operation of the third embodiment.

FIG. 6 is a circuit diagram showing the inside of a light transmitting device according to a fourth embodiment.

FIG. 7 is an operation explanatory diagram for explaining the operation of the fourth embodiment.

FIG. 8 is a block diagram showing a conventional device.

[Explanation of symbols]

 1 Light Transmitter 2 Clock Generator 3 Light Receiver 4 Sample Pulse Generator 5 Sample Hold Circuit 6 Processing Device 7 Object 8 Handle Angle Sensor 9 Vehicle Speed Sensor 11 Drive Voltage Control Circuit 12 Capacitor 13 Resistor 14 Transistor 15 Diode 16 Laser Diode 17 Thyristor 18 lens 19 lens moving device

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] February 22, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

Example 4. The configuration of the fourth embodiment is the same as that of the first embodiment, and only the contents inside the light transmitting device 1 and the processing device 6 are different. FIG. 6 shows the internal structure of the light transmitting device. The difference from the first embodiment in the figure is that the lens moving device 19 can adjust the distance from the laser diode to the lens 18 to control the spread of the transmitted light. As a result, as shown in FIG. 7, when the distance to the obstacle is short, the spread of the transmitted light is increased to reduce the power density. In this case, the light transmission device 1 and the processing device 6 constitute the transmission light control means of claim 7. In addition, by reducing the feed <br/> number of Idemitsu relative angular direction, so as to reduce the power, as delivered light to multiple angular orientations is not irradiated with overlap one person, for human Ensure safety. In this case, the light sending device 1 and the processing device 6 constitute the sending light control means of claims 3 and 6.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

In the obstacle detecting device according to the third aspect of the present invention, the number of transmitted lights is reduced when an obstacle (pedestrian) in a short distance is detected. There is an effect that it is possible to obtain an obstacle detection device that is not unnecessarily limited and is safe for humans.

Claims (7)

[Claims] 1. Light is transmitted in a plurality of angular directions, the presence or absence of an obstacle is detected by the reflected light, and the distances to the obstacles in the plurality of angular directions are detected from the time difference between transmission and reception of the transmitted light and the reflected light. In the obstacle detecting device configured as described above, the obstacle detecting device is provided with a sending light control means for individually controlling the power of the sending light in the plurality of angular directions for each angular direction. 2. The sending light control means is configured to individually control the power of the sending light for each angular direction so that the reception intensity of the reflected light for each angular direction falls within a predetermined range. The obstacle detection device according to claim 1. 3. The obstacle detection device according to claim 1, wherein the transmitted light control means is configured to reduce the number of transmitted light when a short distance is detected. 4. The sending light control means is configured to set the power of the sending light in an angle direction outside the vehicle traveling direction to an intensity smaller than the power of the sending light in the vehicle traveling direction. The obstacle detection device according to claim 1, which is characterized in that. 5. The transmission light control means reduces the power of the transmission light in the angular direction adjacent to the angular direction in which the obstacle is present, when an obstacle at a short distance is detected in a partial angular direction. The obstacle detection device according to claim 1, wherein the obstacle detection device is configured as follows. 6. Light is transmitted in a plurality of angular directions, the presence or absence of an obstacle is detected by the reflected light, and the distances to the obstacles in a plurality of angular directions are detected from the time difference between transmission and reception of the transmitted light and the reflected light. In an obstacle detection device configured to estimate the position, size, etc. of a vehicle based on this, the distance from the obstacle vehicle or the angle direction corresponding to a reflector plate attached to the obstacle vehicle, etc. Transmitted light control that controls the power of the transmitted light in the angle direction portion within a predetermined range with respect to the obstacle vehicle so that the light intensity is sufficiently safe for the occupant of the obstacle vehicle based on parameters such as transmission and reception intensity. An obstacle detection device comprising means. 7. An obstacle detection device for a vehicle configured to detect the presence or absence of an obstacle by the reflected light of the transmitted light and to detect the distance to the obstacle from the time difference between transmission and reception of the transmitted light and the reflected light. An obstacle detection device provided with a transmission light control means configured to widen the angular width of the transmission light when a short distance is detected or the reception intensity of reflected light is higher than necessary.